<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<ul>
    <li>666</li>
</ul>
<script>
    var ul = document.querySelector('ul');
    var li = document.createElement('li');
    ul.appendChild(li);
    var lis = document.createElement('li');
    ul.insertBefore(lis,ul.children[0]);
    ul.removeChild(ul.children[0]);
    var lies = ul.children[0].cloneNode(true);
    ul.appendChild(lies);
</script>
</body>
</html>